PNEUMATIC BOOSTER FOR GENERATING QUICKLY GREAT BRAKE POWER BY SHORTENING A BRAKE AID MECHANISM

摘要

PURPOSE: A pneumatic booster is provided to increase suddenly brake power with reducing operation force by shortening a brake aid mechanism if movement of a plunger for a valve body reaches a predetermined value. CONSTITUTION: In a pneumatic booster(1), a housing is divided into constant and variable pressure chambers by a power piston. A valve unit(12) is opened by moving a plunger(9) disposed in a valve body(2) connected to the power piston by an input rod(11). Pressure difference is generated between the constant and variable pressure chambers by inducing operation gas into the variable pressure chamber. The pressure difference acts thrust generated at the power piston on an output rod(4) through a reaction member(3) and transmits some of reaction force acting on the reaction member from the output rod to the input rod. A brake aid mechanism is interposed between the plunger and the reaction member and shortened if the speed or movement of the plunger about the valve body reaches a predetermined value.